Why no immutable arrays in scala standard library?

Question

Scala has all sorts sorts of immutable sequences like List, Vector,etc. I have been surprised to find no implementation of immutable indexed sequence backed by a simple array (Vector seems way too complicated for my needs).

• Is there a design reason for this? I could not find a good explanation on the mailing list.

• Do you have a recommendation for an immutable indexed sequence that has close to the same performances as an array? I am considering scalaz's ImmutableArray, but it has some issues with scala trunk for example.

Thank you

Answer 1

You could cast your array into a sequence.

val s: Seq[Int] = Array(1,2,3,4) 

The array will be implicitly converted to a WrappedArray. And as the type is Seq, update operations will no longer be available.